The head of Australia's chemical regulator warns the number of key scientists at the agency will halve, as Barnaby Joyce pushes ahead with a $25-million plan to relocate the agency to his own electorate.

Tensions between the ACT's Chief Magistrate Lorraine Walker and the Director of Public Prosecutions get worse, after she delivers a stinging criticism of the DPP's handling of Industrial Court matters.

Stop work notices are issued for Canberra's light rail project after a worker is thrown back two metres by an electric shock, possibly after digging into a live cable with heavy equipment, at a construction site.